U.S. patent application number 12/250286 was filed with the patent office on 2010-04-15 for assisted aspiration catheter system.
This patent application is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to Mark Mallaby.
Application Number | 20100094201 12/250286 |
Document ID | / |
Family ID | 41478950 |
Filed Date | 2010-04-15 |
United States Patent
Application |
20100094201 |
Kind Code |
A1 |
Mallaby; Mark |
April 15, 2010 |
ASSISTED ASPIRATION CATHETER SYSTEM
Abstract
A thrombectomy system comprising an aspiration catheter having
an aspiration lumen and a high pressure irrigation lumen, the
aspiration catheter having a proximal end and a distal, and a
control box fluidly connected to the aspiration catheter and
configured to synchronously provide irrigation and vacuum through
the aspiration catheter.
Inventors: |
Mallaby; Mark; (San Diego,
CA) |
Correspondence
Address: |
CROMPTON, SEAGER & TUFTE, LLC
1221 NICOLLET AVENUE, SUITE 800
MINNEAPOLIS
MN
55403-2420
US
|
Assignee: |
BOSTON SCIENTIFIC SCIMED,
INC.
Maple Grove
MN
|
Family ID: |
41478950 |
Appl. No.: |
12/250286 |
Filed: |
October 13, 2008 |
Current U.S.
Class: |
604/28 ; 604/31;
604/35 |
Current CPC
Class: |
A61B 2217/007 20130101;
A61B 2217/005 20130101; A61M 1/0058 20130101; A61B 2017/22079
20130101; A61M 2205/3317 20130101; A61B 17/32037 20130101 |
Class at
Publication: |
604/28 ; 604/35;
604/31 |
International
Class: |
A61M 1/00 20060101
A61M001/00 |
Claims
1. A thrombectomy system, comprising an aspiration catheter having
an aspiration lumen and a high pressure irrigation lumen, the
aspiration catheter having a proximal end and a distal; and a
control box fluidly connected to the aspiration catheter and
configured to synchronously provide irrigation and vacuum through
the aspiration catheter.
2. The system of claim 1 wherein the control box is configured so
that irrigation cannot be provided without also simultaneously
providing aspiration.
3. The system of claim 1 wherein the control box includes a
pressure/vacuum valve whereby providing irrigation through a first
passage in the control box opens a second passage fluidly connected
to the aspiration lumen.
4. The system of claim 3 wherein the pressure/vacuum valve is a
mechanical valve such that fluid pressure in the first passage
operates the valve.
5. The system of claim 3 wherein the pressure/vacuum valve is
controlled electronically.
6. The system of claim 3 wherein the control box includes a fluid
source hook up, a vacuum source hook up and a displacement pump,
the displacement pump providing irrigation pressure.
7. The system of claim 6 wherein the control box further includes a
control board having a current sensor electrically connected to the
pump and a vacuum pressure sensor to sense vacuum pressure in the
second passage.
8. The system of claim 7 wherein the control board is configured to
cut power to the pump when a reading from the current sensor is out
of a predetermined range.
9. The system of claim 7 wherein the control board is configured to
cut power to the pump when a reading from the current sensor drops
faster than a preset limit.
10. The system of claim 7 wherein the control board is configured
to cut power to the pump when a reading from the vacuum pressure
sensor is out of a predetermined range.
11. The system of claim 3 further comprising a priming valve
fluidly connecting the first and second passages when opened.
12. The system of claim 3, further comprising a vacuum bottle
fluidly connected to the vacuum source hook up.
13. The system of claim 3, further comprising a saline bottle
fluidly connected to the fluid source hook up.
14. The system of claim 6 further comprising tubing fluidly
connecting the control box to the aspiration catheter aspiration
and irrigation lumens.
15. The system of claim 14 wherein operation of the pump produces
fluid pressure pulses and wherein the tubing operates to damping
the fluid pressure pulses.
16. The system of claim 15 wherein the tubing comprises a compliant
polymeric material.
17. The system of claim 15 wherein the catheter irrigation lumen
has a compliancy along a proximal region thereof and wherein the
tubing has a compliancy that is greater than that of the proximal
region of the catheter aspiration lumen.
18. The system of claim 14 further comprising an interface
connector disposed between the tubing and the aspiration catheter
whereby the aspiration catheter is detachable and reattachable to
the tubing.
19. The system of claim 14 wherein the control box is permanently
attached to the tubing and wherein the tubing is permanently
attached to the aspiration catheter.
20. The system of claim 19 further comprising an interface
connector disposed between the tubing and the aspiration
catheter.
21. The system of claim 20 wherein the interface connector further
comprises a filter.
22. The system of claim 18 wherein the connector comprises a filter
fluidly connected between the tubing and the high pressure
irrigation lumen.
23. The system of claim 1 wherein the aspiration catheter
aspiration lumen is defined by a spiral cut metal tube covered by a
polymer sheath.
24. The system of claim 23 wherein the pitch of the spiral cut is
greater in a distal region of the metal tube than in a proximal
region of the metal tube.
25. The system of claim 1 wherein the aspiration catheter
aspiration lumen has a distal opening and wherein the aspiration
lumen high pressure irrigation lumen has a distal orifice, wherein
the distal orifice is proximal of the distal opening by at least
0.02 cm.
26. The system of claim 25 wherein the distal orifice is configured
to release a jet of irrigation fluid across the width of the
aspiration lumen.
27. The system of claim 25 wherein the distal orifice is further
configured such that the jet of irrigation fluid is released normal
to a longitudinal axis of the aspiration lumen.
28. A method of removing a thrombus, comprising the steps of:
providing the system of claim 1; inserting the aspiration catheter
percutaneously into a body vessel lumen; advancing the aspiration
catheter to a region of interest; and operating the control box to
synchronously provide high pressure irrigation and aspiration
through the aspiration catheter to draw the thrombus into the
aspiration lumen.
29. The method of claim 1 wherein the system of claim 1 is the
system of claim 4.
30. The method of claim 1 wherein the system of claim 1 is the
system of claim 11 and further comprising the step of, prior to the
step of inserting the aspiration catheter, operating the priming
valve to evacuate air from the pump.
Description
TECHNICAL FIELD
[0001] The present disclosure pertains generally to medical devices
and methods of their use. More particularly, the present invention
pertains to aspiration and thrombectomy devices and methods of use
thereof.
BACKGROUND
[0002] Several devices and systems already exist to aid in the
removal of thrombetic material. These include simple aspiration
tube type devices using vacuum syringes to extract thrombus into
the syringe, simple flush-and-aspirate devices, more complex
devices with rotating components the pull in, macerate and
transport thrombetic material away from the distal tip using a
mechanical auger, systems that use very high pressure to macerate
the thrombus and create a venturi effect to flush the macerated
material away.
[0003] All of the devices described above have limitations as a
result of individual design characteristics. For example, simple
aspiration catheters off ease of use and rapid deployment but may
become blocked or otherwise inoperable when faced with older, more
organized thrombetic material. Such devices must be removed and
cleared outside the body and then re-inserted into the vasculature,
which lengthens the time needed for the procedure and increases the
opportunity to kink the catheter shaft. Such kinks may reduce
performance by decreasing the cross-sectional area of the catheter
or may render the device inoperable. The use of a syringe to
provide vacuum, moreover, may increase the risk of operator error
by not preventing the operator from applying positive pressure to
the aspiration lumen and thereby expelling loose embolic material
into the patient vasculature.
[0004] Mechanical rotary devices use an auger to grab and carry the
thrombus away from the target area. Some create transport force via
vacuum bottles while others create differential pressure at the
distal tip of the device with the auger acting as a low pressure
pump. These devices typically work slowly and offer the physician
no feedback as to when the device should be advanced further into
the lesion.
[0005] Flushing type devices include manual flush type devices in
which the physician manipulates a hand-driven pump to provide
flowing saline at the tip of the device to break up and aspirate
the thrombus material, which may introduce performance variations
based on the ability of the physician to consistently pump the
device over the duration of the procedure. Flushing devices also
include high pressure flushing devices that macerate the thrombus
and then, using a vortex created by the high pressure fluid,
transport the emulsified thrombetic material to a collection bag.
These devices are effective at removing all levels of thrombetic
material, but the pressure created by the device is so great that
its action against certain vessel walls may interrupt the heart
muscle stimulation mechanism and creates a bradycardia event in
certain patients that requires a pacing lead to be placed in the
patient prior to use. Further, interacting with the thrombetic
material outside of the catheter may allow loose material to escape
the capture mechanism.
[0006] Thus, a need remains for improved thrombus removal
capability particularly for systems that have increased
reliability, are more benign and offer greater feedback
capabilities.
SUMMARY
[0007] The disclosure pertains generally to devices such as an
assisted aspiration catheter for removing a range of thrombetic
material from the general vascular system, natural or synthetic
tubule or cavity found in the human body of a patient via standard
vascular access using the Seldinger technique.
[0008] In one illustrative but non-limiting example, a vacuum
source is connected to the proximal end of a flexible, kink
resistant tube or aspiration lumen or catheter. The other end of
the aspiration lumen is open to patient vasculature to allow
thrombetic material to be drawn into the aspiration lumen via the
suction provided by the vacuum source. The vacuum source may also
act as a containment vessel for aspirated thrombetic material. A
second flexible tube that may be housed inside the aspiration lumen
conveys a pressurized stream of sterile saline or other physiologic
solution to a specifically placed orifice near the distal end of
the aspiration lumen. A control system may be provided that ensures
the synchronous operation of the vacuum source and the pressurized
stream. Thereby thrombetic material may be drawn by vacuum into the
distal opening of the catheter. Less organized thrombetic material
may be immediately aspirated into the containment vessel and more
organized thrombetic material may be removed by being drawn into
the catheter and is macerated by a high-pressure fluid stream
within the catheter opening and aspirated into the containment
vessel.
[0009] The above summer summary of some embodiments is not intended
to describe each disclosed embodiment or every implementation of
the present invention. The Figures and Detailed Description that
follow more particularly exemplify these embodiments.
BRIEF DESCRIPTION OF THE FIGURES
[0010] FIG. 1 is a diagrammatic view of as assisted aspiration
catheter system 10;
[0011] FIG. 2 is a diagrammatic view showing more detail of the
proximal portion of assisted catheter aspiration system 10; and
[0012] FIG. 3 is a diagrammatic view of the distal end portion of
assisted catheter aspiration system 10.
[0013] While the invention is amenable to various modifications and
alternative forms, specifics thereof have been shown by way of
example in the drawings and will be described in detail. It should
be understood, however, that the intention is not to limit the
invention to the particular embodiments described. On the contrary,
the intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the claims.
DETAILED DESCRIPTION
[0014] For the following defined terms, these definitions shall be
applied, unless a different definition is given in the claims or
elsewhere in this specification.
[0015] All numeric values are herein assumed to be modified by the
term "about," whether or not explicitly indicated. The term "about"
generally refers to a range of numbers that one of skill in the art
would consider equivalent to the recited value (i.e., having the
same function or result). In many instances, the terms "about" may
include numbers that are rounded to the nearest significant
figure.
[0016] The recitation of numerical ranges by endpoints includes all
numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3,
3.80, 4, and 5).
[0017] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" include plural referents unless
the content clearly dictates otherwise. As used in this
specification and the appended claims, the term "or" is generally
employed in its sense including "and/or" unless the content clearly
dictates otherwise.
[0018] The following detailed description should be read with
reference to the drawings in which similar elements in different
drawings are numbered the same. The drawings, which are not
necessarily to scale, depict illustrative embodiments and are not
intended to limit the scope of the invention.
[0019] FIG. 1 is a diagrammatic figure depicting assisted
aspiration system 10. Aspiration system 10 includes a remote hand
piece 12 that contains the fluid pump and the operator control
interface. In one contemplated embodiment, system 10 is a single
use disposable unit. Aspiration system 10 may also include
extension tubing 14, which contains lumens both for fluid
irrigation and for aspiration, and which allows independent
manipulation of a catheter 16 without requiring repositioning of
hand piece 12 during the procedure. Extension tubing 14 may also
act as a pressure accumulator. High pressure fluid flow from the
displacement pump pulses with each stroke of the pump creating a
sinusoidal pressure map with distinct variations between the peaks
and valleys of each sine wave. Extension tubing 14 may be matched
to the pump to expand and contract in unison with each pump pulse
to reduce the variation in pressure caused by the pump pulses to
produce a smooth or smoother fluid flow at tip of catheter 16. Any
tubing having suitable compliancy characteristics may be used. The
extension tubing may be permanently attached to the pump or it may
be attached to the pump by a connector. The connector is preferably
configured to ensure that the extension tubing cannot be attached
to the pump incorrectly.
[0020] An interface connector 18 joins extension tubing 14 and
catheter 16 together. In one contemplated embodiment, interface
connector 18 may contain a filter assembly (not shown) between high
pressure extension tubing 16 and the high pressure lumen of
catheter 16. The catheter and extension tube may be permanently
joined by connector 18. Alternatively, interface connector 18 may
contain a standardized connection so that a selected catheter 16
may be attached to extension tubing 14.
[0021] Attached to hand piece 12 are a fluid source 20 and a vacuum
source 22. A standard hospital saline bag may be used as fluid
source 20; such bags are readily available to the physician and
provide the necessary volume to perform the procedure. Vacuum
bottles may provide the vacuum source 22 or the vacuum source may
be provided by a syringe, a vacuum pump or other suitable vacuum
source.
[0022] In one contemplated embodiment, catheter 16 has a variable
stiffness ranging from stiffer at the proximal end to more flexible
at the distal end. The variation in the stiffness of catheter 16
may be achieved with a single tube with no radial bonds between two
adjacent tubing pieces. For example, the shaft of catheter 16 may
be made from a single length of metal tube that has a spiral cut
down the length of the tube to provide shaft flexibility. Variable
stiffness may be created by varying the pitch of the spiral cut
through different lengths of the metal tube. For example, the pitch
of the spiral cut may be greater (where the turns of the spiral cut
are closer together) at the distal end of the device to provide
greater flexibility. Conversely, the pitch of the spiral cut at the
proximal end may be lower (where the turns of the spiral cut are
further apart) to provide increased stiffness. A single jacket
covers the length of the metal tube to provide for a vacuum tight
catheter shaft. Other features of catheter 16 are described with
reference to FIG. 3, below.
[0023] FIG. 2 is a diagrammatic view showing more detail of hand
piece 12 and the proximal portion of assisted catheter aspiration
system 10. Hand piece 12 includes a control box 24 where the power
and control systems are disposed. A pump 26 may be motor driven
displacement pump that has a constant output of less than 30% of
the total aspiration volume, based on the minimum catheter
dimensions. This pump displacement to catheter volume ensures that
no energy is transferred to the patient from the saline pump as all
pressurized fluid is evacuated by the aspiration lumen. A prime
button 28 is mechanically connected to a prime valve 30. When
preparing the device for use, it is advantageous to evacuate all
air from the pressurized fluid system to reduce the possibility of
air embolization. By depressing prime button 28, the user connects
fluid source 20 to vacuum source 22 via the pump 26. This
forcefully pulls fluid through the entire pump system, removing all
air and positively primes the system for safe operation. A
pressure/vacuum valve 32 is used to turn the vacuum on and off
synchronously with the fluid pressure system. One contemplated
valve 32 is a ported one way valve. Such a valve is advantageous
with respect to manual or electronic valve systems because it acts
as a tamper proof safety feature by mechanically and automatically
combining the operations of the two primary systems. By having
pressure/vacuum valve 32, the possibility of turning the vacuum on
without activating the fluid system is eliminated.
[0024] An electronic control board (not shown) is used to provide
the operator interface by use of switches and indicator lamps. The
control board also monitors and controls several device safety
functions, which include over pressure and air bubble detection and
vacuum charge. In one contemplated embodiment, the pump pressure is
proportional to the electric current needed to produce that
pressure. Consequently, if the electric current required by pump 26
exceeds a preset limit, the control board will disable the pump by
cutting power to it. Air bubble detection may also be monitored by
electrical current going to the pump. In order for a displacement
pump to reach high fluid pressures, there should be little or no
air (which is highly compressible) present in the pump or
connecting system. The fluid volume is small enough that any air in
the system will result in no pressure being generated at the pump
head. The control board monitors the pump current for any abrupt
downward change that may indicate that air has entered the system.
If the rate of drop is faster than a preset limit, the control
board will disable the pump by cutting power to it until the
problem is corrected. The vacuum line may be connected to a
negative pressure sensor. If the vacuum is vacuum source 22 is low
or if a leak is detected in the vacuum system, the control board
disables the pump until the problem is corrected. The vacuum sensor
may also be part of the safety circuit that will not allow the pump
to run if vacuum is not present. Thereby a comprehensive safety
system that requires both pump pressure and vacuum pressure for the
system to run. If a problem exists, the control board will not
allow the user to operate the device until all problems are
corrected.
[0025] FIG. 3 is a diagrammatic view of the distal end portion of
assisted catheter aspiration system 10, showing more details of
catheter 16. Catheter 16 is a single-operator exchange catheter and
includes a short guidewire lumen 34 attached to the distal end of
the device. Guidewire lumen can be between 1 and 30 cm in length,
more preferable between 5 and 25 cm in length, or between 5 and 20
cm in length, or approximately 15 cm in length. Aspiration lumen 38
includes a distal opening 40 to allow the vacuum to draw thrombetic
material into the lumen. A high pressure lumen 36 includes a distal
orifice 42 that is set proximally of distal opening 40 by a set
amount. For example, distal orifice 42 can be set proximally of
distal opening 40 by about 0.020'', more preferably by
0.020''+-0.003'' or by another desired amount. Orifice 42 is
configured to spray across the aspiration lumen to dilute the
thrombetic material for transport to vacuum source 22. The axial
placement of the fluid orifice 42 is such that the spray pattern
interaction with the opposing lumen wall preferably produces a
spray mist and not a swirl pattern that could force embolic
material out from the distal opening 40. The irrigation fluid
preferably leaves orifice 42 at between 200 and 450 psi and more
preferably at between 250 and 300 psi.
[0026] Other contemplated catheters are disclosed in co-pending
application Ser. No. 12/026,317 to Jensen et al., entitled
"Thrombectomy Apparatus and Method" and filed Feb. 5, 2008, which
is incorporated by reference.
[0027] In some cases, parts or all of the devices described herein
may be doped with, made of, coated with, or otherwise include a
radiopaque material. Radiopaque materials are understood to be
materials capable of producing a relatively bright image on a
fluoroscopy screen or another imaging technique during a medical
procedure. Some examples of radiopaque materials can include, but
are not limited to, gold, platinum, palladium, tantalum, tungsten
alloy, polymer material loaded with a radiopaque filler, and the
like.
[0028] In some instances, a degree of MRI compatibility may be
imparted into parts of the devices described herein. For example,
to enhance compatibility with Magnetic Resonance Imaging (MRI)
machines, it may be desirable to make various portions of the
devices described herein from materials that do not substantially
distort MRI images or cause substantial artifacts (gaps in the
images). Some ferromagnetic materials, for example, may not be
suitable as they may create artifacts in an MRI image. In some
cases, the devices described herein may include materials that the
MRI machine can image. Some materials that exhibit these
characteristics include, for example, tungsten,
cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as
ELGILOY.RTM., PHYNOX.RTM., and the like),
nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as
MP35-N.RTM. and the like), nitinol, and the like, and others.
[0029] In some instances, some of the devices described herein may
include a coating such as a lubricious coating or a hydrophilic
coating. Hydrophobic coatings such as fluoropolymers provide a dry
lubricity. Lubricious coatings improve steerability and improve
lesion crossing capability. Suitable lubricious polymers are well
known in the art and may include silicone and the like, hydrophilic
polymers such as high-density polyethylene (HDPE),
polytetrafluoroethylene (PTFE), polyarylene oxides,
polyvinylpyrrolidones, polyvinylalcohols, hydroxy alkyl
cellulosics, algins, saccharides, caprolactones, and the like, and
mixtures and combinations thereof. Hydrophilic polymers may be
blended among themselves or with formulated amounts of water
insoluble compounds (including some polymers) to yield coatings
with suitable lubricity, bonding, and solubility.
[0030] It should be understood that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size, and arrangement of steps
without exceeding the scope of the invention. The scope of the
invention is, of course, defined in the language in which the
appended claims are expressed.
REFERENCE NUMERAL LIST
[0031] 10 Assisted Aspiration Catheter System [0032] 12 Hand Piece
[0033] 14 Extension Tubing [0034] 16 Catheter [0035] 18 Connector
[0036] 20 Fluid Source [0037] 22 Vacuum Source [0038] 24 Control
Box [0039] 26 Pump [0040] 28 Prime Button [0041] 30 Prime Valve
[0042] 32 Pressure/Vacuume Valve [0043] 34 Guidewire Lumen [0044]
36 High Pressure Lumen [0045] 38 Aspiration Lumen [0046] 40 Distal
Opening [0047] 42 Orifice
* * * * *